Had real trouble getting a CK race on a steel fork recently with the waste pipe trick, just would go.
Heated the race up on the hob, not for too long, placed it over the steerer & womp, fell straight down over the lip & seated perfectly, I was amazed!

Nikk, there'll be a gap at the back but it's not open- it's against the fork so closed off anyway. Or at least, this is how it works out with my Cane Creeks.

The Hope seal doesn't seem to be too good at all tbh, it was more of a shield than a seal on mine, didn't really make contact with the cups. But still, those pics show one seriously grotty headset, top and bottom!